Si86xx CMOS Digital Isolator-Based Serial Interface User’s Guide

Si86xxCOM-EVB
S i 8 6 X X C M O S D I G I TA L I S O L A T O R - B A S E D S E R I A L
I N T E R F A C E U S E R ’S G U I D E
1. Introduction
SI86xx devices are CMOS-based galvanic isolators (1 kV/2.5 kV/5 kV) designed for industrial, commercial, and
medical isolation applications. They are available in various channel counts (1/2/3/4/5/6), speeds (1 and
150 Mbps), and options in two package options (narrow and wide body SOIC). They are also available in
unidirectional or bidirectional (I2C) channels option.
2. Kit Contents
The Si86xxCOM Evaluation Board contains the following items:

Si86xxCOM evaluation board show casing:
Si8642BB
4-channel unidirectional 1 Mbps digital isolator, narrow body, 2.5 kV
2-channel unidirectional 150 Mbps digital isolator, narrow body, 2.5 kV
Si8622ED 2-channel unidirectional 1 Mbps digital isolator, wide body, 5 kV*
*Note: The creepage and clearance are defined by the narrow-body SOIC (2.5 kV) isolators used in the EVB and must NOT be
used for 5 kV isolation testing.
Si8621BB
2.1. Hardware Overview
The Si86xxCOM Evaluation Board implements the isolated physical layer for RS232, RS422/485, and CAN bus
serial transceivers. Key features include:
Isolated RS232 transceiver: Maximum data rate of 1 Mbps. Isolated TXD, RXD, RTS, and CTS signals with
DB9 connector interface.
 Isolated 4 Wire RS422/485: Maximum data rate of 52 Mbps; failsafe full duplex with passive flow control. DB9
and RJ45 connectors.
 Isolated CAN Bus: Maximum data rate of 1 Mbps, which implements the ISO 11898-3 physical layer and DB9
connector.
A top-level hardware block diagram is shown in Figure 1. The RS232 and RS422/RS485 isolated transceivers
operate as a repeater, and the CAN Bus interface operates as an isolated controller-side interface.

Figure 1. Top-Level Hardware Overview
Rev. 0.1 4/15
Copyright © 2015 by Silicon Laboratories
Si86xxCOM-EVB
Si86xxCOM-EVB
Figure 2. Si86xxCOM Evaluation Board
The evaluation board photo of Figure 2 shows the Silicon Labs Si86xx digital isolators placed at the center of the
board. The RS232 and 422/485 isolated transceivers are implemented with narrow-body, 2.5 kV Si8642BB and
Si8621BB digital isolators. The medical grade CAN bus interface is implemented with a wide-body Si8622ED
digital isolator rated at 5 kV.*
*Note: The creepage and clearance are defined by the narrow-body SOIC (2.5 kV) isolators used in the EVB and must NOT be
used for 5 kV isolation testing.
3. Required Equipment







Two dc power supplies (isolated)
Two red and black banana-to-banana cables
One straight-through RS232 cable (3'3, 2'2) (e.g. StarTech Model#MXT100_25)
One crossover (null modem) RS232 cable (3'2, 2'3) (e.g. StarTech Model # SCNM9FM)
One PC with COM1 port
Si86xxCOM evaluation board (under test)
Si86xxCOM User's Guide (this document)
3.1. Optional Equipment
(User Can Test the Functionality of Standalone EVB Using the Following Equipment)
One 4-channel oscilloscope, 250 MHz BW (e.g., TDS784A)
Dual output Pattern/Function generator, 80 MHz data rate (e.g., Agilent 81104A)
 Two BNC to hook cable (e.g., Pomona #3788)


2
Rev. 0.1
Si86xxCOM-EVB
4. Hardware Overview and Demo
The Si86xxCOM evaluation board operates from 4.75 to 5.25 V. Each isolated interface is enabled or disabled by
jumper option settings as shown in Figures 3, 4, and 5 (RS232, RS422/485 and CAN Bus isolated interfaces,
respectively).
Refer to Figure 3:
J3,J5
J9,J6
 J15,J16
 J1,J2
 J4,J7,J8,J10
Refer to Figure 4:
Connector for +5 V bus (J3) and GND(J5) plane
Connector for +5VISO bus (J9) and ISOGND(J6) plane
Header 2x1, Supply for RS232 interface
DB9 Female (J1) and Male (J2) connector for RS232
Header 2x1, RS232 loopback test enable

J17, J18
J11,J12
 RJ1,RJ2
Refer to Figure 5:
Header 2x1, Supply for RS422/485 interface
DB9 Female (J1) and Make (J2) connector for RS422/485
RJ45 connector for RS422/485
J19,J20
 J13,J14
Header 2x1, Supply for CAN Bus interface
DB9 Female (J13) and Male (J14) connector for CAN bus




Figure 3. Power Supply Input and Isolated RS232 Interface
Rev. 0.1
3
Si86xxCOM-EVB
Figure 4. Isolated 4-Wire R422/485 Interface
Figure 5. Isolated CAN Bus Interface
4.1. Common Board Setup
Perform the following steps for a common board setup:
1. Turn on the dc power supplies, and set the output voltage to 5.0 V, 500 mA current limit.
2. Connect red banana cables to each of the positive outputs of the power supply, and connect the black banana
cables to the respective negative or 0 V output.
3. Turn off the dc power supply.
4. Connect the other end of one of the red banana cables to J3 (+5 V) and the other end of the second red banana
cable to J9 (+5VISO).
5. Connect the other end of the black banana cable to J5 (GND) and J6 (ISOGND), respectively.
This completes the power supply connections to the board.
4
Rev. 0.1
Si86xxCOM-EVB
4.2. Isolated RS232 interface Setup
Perform the following steps for an isolated RS232 interface setup:
1. Power up a PC with the COM1 port (Male DB9 connector).
2. Connect one end of the straight-through RS232 cable to the COM1 port and the other end to J1 of the
evaluation board. Table 1 lists the standard pin definitions of the interface.
Table 1. Isolated RS232 Pin Definitions
J1 DB9 (Female)
Pinout
RS232 Signal Name
J2 DB9 (Male)
Pinout
1,4,6,9
NC
1,4,6,9
2
RXD
2
3
TXD
3
5
GND
5
7
RTS
7
8
CTS
8
3. On the J2 side, use straight-through cable when connecting to DCE (Modem) and crossover cable when
connecting to DTE (PC, printers, PLCs etc). Refer to Figures 6 and 7.
4. Shunt jumpers J15 and J16 to apply power to the circuit.
5. Turn ON the dc power supply.
The board under test is ready to transfer data.*
*Note: Most PCs support data rates up to 115 kbps, but the onboard transceiver and isolator can support a maximum data rate
of 1 Mbps.
Figure 6. DTE to DCE Connection
Rev. 0.1
5
Si86xxCOM-EVB
Figure 7. DTE to DTE Connection
4.3. Isolated RS422/485 Interface Setup
The RS422 and RS485 standards are based on a balanced differential line. The RS422 interface is typically
implemented as a 4-wire, point-to-point communication system, whereas RS485 can be implemented in a 2-wire or
4-wire multipoint configuration.
Note: This EVB implements a full-duplex, isolated 4-wire RS422/RS485 interface with automatic flow control and should NOT
be used to implement a 2-wire interface
Please note that the RS422/485 standard does not recommend a specific connector or pinout like the RS232
standard. In light of this, the EVB has DB9 and 8-pin-RJ45 connectors for flexibility, allowing the user to choose
and follow the pinout definition table for proper cabling.
Proper termination is required at each end of the cable for reliable communication links and long wiring runs. The
EVB has place holders (RTERM1-4) for termination resistors to match the characteristic impedance of the cable
specified by the manufacturer. A typical value is around 120 . The RS422/RS485 transceivers used in the EVB
have 22 k receiver input resistance and a fail-safe feature that guarantees the receiver output HIGH when inputs
are left open or shorted.
Perform the following steps for interface setup:
1. Turn off the dc power supplies (if they are not turned off already).
2. Shunt jumpers J17 and J18 to apply power to the circuit.
3. Refer to Table 2 for the RS422/485 connector pinout definition. Make sure the cable is made to this pinout
definition.
4. Recommended cables are 24 AWG 2 twisted pair with shield (e.g., Belden 9842-500).
5. A simple 4-wire master slave point-to-point connection is shown in Figure 8 for reference.
Connect the transmitter output of the master node to the receiver input (J12.1 and J12.2) of the EVB board.
Connect the transmitter output (J12.3 and J12.4) of the EVB to the receiver input of the master node.
 Connect the isolated transmitter output (J11.1 and J11.2) of the EVB board to the receiver input of the slave
node. Connect the transmitter output of the slave node to the isolated receiver input (J11.4 and J11.3) of the
EVB.
6. Turn on the dc power supply.

7. The EVB is ready for data transfer and can support a maximum data rate of 52 Mbps.
6
Rev. 0.1
Si86xxCOM-EVB
Table 2. RS422/485 Pinout Definition for DB9 and RJ45 Connector
J12
(Female DB9)
Pinout
RS422/485 Signal
Name
J11
(Male DB9) Pinout
RS422/485 Signal
Name
1
A (RxD+)
1
Y(TxD+)
2
B (RxD–)
2
Z(TxD–)
3
Z (TxD–)
3
B(RxD–)
4
Y (TxD+)
4
A(RxD+)
5
GND
5
GND
6,7,8,9
NC
6,7,8,9
NC
RJ1
Pinout
RS422/485 Signal
Name
RJ2
Pinout
RS422/485 Signal
Name
1,7,8
NC
1,7,8
NC
2
Y (TxD+)
2
A (RxD+)
3
Z (TxD–)
3
B(RxD–)
4
GND
4
GND
5
B (RxD–)
5
Z (TxD–)
6
A (RxD+)
6
Y (TxD+)
Figure 8. Simple Point-to-Point RS422/485 Connection
Rev. 0.1
7
Si86xxCOM-EVB
4.4. Isolated CAN Bus Interface Setup
CAN (Controller Area Network) Bus is a bidirectional, 2-wire (CANH and CANL) differential signaling bus with a
data rate up to 1 Mbps. The CAN bus signal has two states: recessive (logic High) and dominant (logic Low). When
no driver is active, the bus is in the recessive state (CANH= CANL). The non-bus side of the transceiver is
connected to a controller. The EVB implements an isolated controller-side CAN interface as shown in Figure 1. The
speed/slope control resistor RSPD is tied to GND for high-speed (1 Mbps) operation. Users can increase the value
of resistor RSPD for slower operation.
The CAN bus must be properly terminated at each end of the cable. The EVB comes with a standard termination of
120  (RTERM8) installed. The Si8622ED digital isolator powers up with default high output making sure the CAN
bus is in a recessive state.
Perform the following steps for interface setup:
1. Turn the power supply off, if it is not off already.
2. Shunt jumpers J19 and J20 to apply power to the circuit.
3. Standard twisted pair (24 AWG, ex HYCANBUS0901) with or without shield can be used. Refer to Table 3 for
pinout definition. Make sure the cable is made to this pinout definition.
4. A typical connection to the EVB is shown in Figure 9.
Connect the controller side driver output and receiver input to the J13.3 (DR) and J13.2 (RX) pins of EVB
respectively.
 Connect the CANH (J14.7) and CANL (J14.2) of the EVB to the bus lines.
5. Turn on the dc power supply.

The EVB is ready for data transfer and can support a maximum data rate of 1 Mbps.
Table 3. CAN Bus Interface Pinout Definition
J13
(Female DB9)
Pinout
CAN Bus
Signal Name
J14
(Male DB9)
Pinout
CAN Bus
Signal Name
1,4,6,7,8,9
NC
1,4,5,6,8,9
NC
2
RX
(Receiver Output)
2
CANL
3
DR (Driver Input)
3,6
GND
5
GND
7
CANH
Figure 9. Isolated CAN Bus Interface Connection
8
Rev. 0.1
J1
DB9
Rev. 0.1
GND
RXD
RTS
TXD
CTS
TP22
J8
TP21
0.47uF
C29
TP23
J10
0.47uF
C30
CTS
RXD
RTS
TXD
8
2
6
14
7
13
C3
1uF
C15
C1+
C1-
C2+
C2-
T1IN
T2IN
R1OUT
R2OUT
0.1uF
V+
V-
T1OUT
T2OUT
R1IN
R2IN
Gauranteed 460 kbit/s
Operates From a Single 3.3V- 5.5V Power Supply
SP3232EH/MAX3232 RS232 TxRx Spec:
TP54
TP53
TP49
1
6
2
7
3
8
4
9
5
TP20
U1
15
GND
VCC
16
C5
C2
0.1uF
0.47uF
TP3
TP4
TP2
+5V0_RS232
1uF
C1
J15
7
6
5
4
3
Si8642
EN1
A4
A3
A2
A1
IC1
+5V0_RS232
EN2
B4
B3
B2
B1
10
11
12
13
14
+5V0_ISORS232
TP5
TP6
TP7
1uF
TP24
C12
C11
ISOGND
C10
+5V0_ISORS232
0.1uF
C14
J16
+5V_ISO
0.47uF
0.1uF
5
4
3
1
9
12
10
11
Figure 10. Isolated RS232 Interface Schematic
+5V0_RS232
1
3
4
5
11
10
12
9
TP1
0.1uF
C6
+5V
ISOLATION
Isolated RS232 Interface
1
VDD1
GND1
GND1
8
2
16
VDD2
GND2
GND2
9
15
R2OUT
R1OUT
T2IN
T1IN
C2-
C2+
C1-
C1+
U2
R2IN
R1IN
T2OUT
T1OUT
V-
V+
+5V0_ISORS232
16
VCC
GND
15
GND
TXD_ISO
RTS_ISO
RXD_ISO
CTS_ISO
7
13
8
0.47uF
14
6
C31
0.1uF
1uF
2
C16
C4
TP27
J4
TP28
J7
TP26
TP25
0.47uF
C32
ISOGND
RXD_ISO
RTS_ISO
TXD_ISO
CTS_ISO
TP57
TP56
TP55
J2
DB9 MALE RA
1
6
2
7
3
8
4
9
5
Si86xxCOM-EVB
5. Schematics
9
Rev. 0.1
9
10
7
8
3
6
1
2
4
5
GND
NI
RTERM2
NI
RTERM1
TP9
TP8
TP10
TP11
NI
RBIAS2
VCC = 5.0V
Low supply current: 7mA max
Designed for 52 Mbps operation
RS-485/RS-422 protocol compatible
NI
RBIAS1
+5V0_RS485
LTC1686 RS422/485 TxRx Spec:
TP48
TP45
TP44
TP30
Molex RJ45
SHLD1
SHLD2
PAIR4_1
PAIR4_2
PAIR3_1
PAIR3_2
PAIR2_1
PAIR2_2
PAIR1_1
PAIR1_2
RJ1
J12
DB9
1
6
2
7
3
8
4
9
5
Y
Z
B
A
U3
0.1uF
C19
LTC1686
GND
D
R
VDD
4
3
2
1
1uF
C9
0.1uF
C17
J17
+5V0_RS485
TP13
TP12
1uF
C7
+5V
3
2
Si8621
A2
A1
IC2
+5V0_RS485
B2
B1
6
7
+5V0_ISORS485
1uF
0.1uF
TP15
TP14
C8
C18
J18
+5V_ISO
ISOGND
1
2
3
4
VDD
R
D
GND
LTC1686
A
B
Z
Y
0.1uF
1uF
U4
C20
C13
+5V0_ISORS485
8
7
6
5
NI
RBIAS4
NI
TP19
TP17
RBIAS3
+5V0_ISORS485
Figure 11. Isolated RS422/485 Interface Schematic
5
6
7
8
GND
1
VDD1
GND1
4
8
VDD2
GND2
5
10
ISOLATION
Isolated RS485 Interface
TP18
NI
RTERM4
NI
RTERM3
TP16
9
10
7
8
3
6
1
2
4
5
RJ2
J11
DB9 MALE RA
TP52
TP51
TP50
TP29
Molex RJ45
SHLD1
SHLD2
PAIR4_1
PAIR4_2
PAIR3_1
PAIR3_2
PAIR2_1
PAIR2_2
PAIR1_1
PAIR1_2
ISOGND
1
6
2
7
3
8
4
9
5
Si86xxCOM-EVB
Rev. 0.1
1uF
8
7
6
5
4
3
2
1
NC
GND1
NC
A2
A1
VDD1
NC
GND1
IC3
+5V0_CAN
Si8622
GND2
NC
NC
B2
B1
VDD2
NC
GND2
9
10
11
12
13
14
15
16
+5V0_ISOCAN
TP34
TP42
0.1uF
C28
RXD
VCC
VREF
CANL
CANH
RS
PCA82C251
GND
TXD
U6
TP43
4
3
2
1
Figure 12. Isolated CAN bus Interface Schematic
1uF
C27
+5V0_ISOCAN
RISO
DISO
1uF
TP33
C23
C24
ISOGND
0.1uF
J20
+5V_ISO
* Si8622ED Default High Output is required for CAN interface
TP32
TP31
C21
C22
J19
0.1uF
+5V
*Other pin compatible CAN TxRx are L9616-ND & SN65HVD1050
1Mbps data rate
5V operation
PCA82C251T/N3* CAN TxRx Spec:
TP36
TP35
J13
DB9
1
6
2
7
3
8
4
9
5
J21
1K
RPU1
GND
ISOLATION
Isolated CAN Bus Interface
5
6
7
8
NI
RPU3
TP40
0
RSPD1
NI
RPU4
120
RTERM8
TP38
TP37
TP39 TP41
J14
DB9 MALE RA
1
6
2
7
3
8
4
9
5
Si86xxCOM-EVB
11
Si86xxCOM-EVB
6. Si86xxCOM Bill Of Materials
Table 4. Si86xxCom Bill of Materials
Quantity
Reference
Value
Voltage Tolerance
Type
ManufacturerPN
Manufacturer
11
C1, C3, C4, C7, C8, C9,
C10, C13, C21, C23, C27
1 µF
16 V
±20%
X7R
C0805X7R160-105M Venkel
6
C2, C12, C29, C30, C31,
C32
0.47 µF
16 V
±10%
X7R
C0805X7R160-474K Venkel
13
C5, C6, C11, C14, C15,
C16, C17, C18, C19, C20,
C22, C24, C28
0.1 µF
16 V
±10%
X7R
C0805X7R160-104K Venkel
1
IC1
Si8642
Isolator
Si8642BB-B-IS1
SiLabs
1
IC2
Si8621
Isolator
Si8621BB-B-IS
SiLabs
1
IC3
Si8622
Isolator
Si8622ED-B-IS
SiLabs
3
J1, J12, J13
DB9
D-SUB
D09S33E4GX00LF
FCI
3
J2, J11, J14
DB9 MALE
RA
D-SUB
D09P33E4GX00LF
FCI
2
J3, J9
RED
BANANA
111-0702-001
Johnson/
Emerson
11
J4, J7, J8, J10, J15, J16,
J17, J18, J19, J20, J21
JUMPER
Header
TSW-102-07-T-S
Samtec
2
J5, J6
BLACK
BANANA
111-0703-001
Johnson/
Emerson
4
MH1, MH2, MH3, MH4
4-40
HDW
NSS-4-4-01
Richco
Plastic Co
1
PCB1
Si86xxCOM-EVB
REV 1.0
PCB
Si86xxCOM-EVB
REV 1.0
SiLabs
2
RJ1, RJ2
Molex RJ45
1
RPU1
1K
1
RSPD
0
1
RTERM8
4
SO1, SO2, SO3, SO4
12
120
Connector 85505-5113
±1%
ThickFilm CR0805-10W-1001F Venkel
ThickFilm CR0805-10W-000
±1%
STANDOFF
Venkel
ThickFilm CR0805-10W-1200F Venkel
HDW
Rev. 0.1
Molex
1902D
Keystone
Electronics
Si86xxCOM-EVB
Table 4. Si86xxCom Bill of Materials (Continued)
Quantity
Reference
Value
55
TP1, TP2, TP3, TP4, TP5,
TP6, TP7, TP8, TP9, TP10,
TP11, TP12, TP13, TP14,
TP15, TP16, TP17, TP18,
TP19, TP20, TP21, TP22,
TP23, TP24, TP25, TP26,
TP27, TP28, TP29, TP30,
TP31, TP32, TP33, TP34,
TP35, TP36, TP37, TP38,
TP39, TP40, TP41, TP42,
TP43, TP44, TP45, TP48,
TP49, TP50, TP51, TP52,
TP53, TP54, TP55, TP56,
TP57
WHITE
2
U1, U2
MAX3232
1
U2
PCA82C25
1
2
U3, U4
Voltage Tolerance
Type
Loop
5.5 V
RS232
CAN Bus
LTC1686
ManufacturerPN
Manufacturer
151-201-RC
Kobiconn
MAX3232CSE+
Maxim
PCA82C251T
NXP
LTC1686CS8
Linear Tech
Not Installed
10
RBIAS1, RBIAS2, RBIAS3,
RBIAS4, RPU3, RPU4,
RTERM1, RTERM2,
RTERM3, RTERM4
0
ThickFilm CR0805-10W-000
Rev. 0.1
Venkel
13
Si86xxCOM-EVB
7. Ordering Guide
Table 5. Ordering Guide
14
Ordering Part
Number
Description
Si86xxCOM-RD
Isolated serial communication evaluation board
Rev. 0.1
Si86xxCOM-EVB
NOTES:
Rev. 0.1
15
Smart.
Connected.
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Quality
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Silicon Laboratories Inc.
400 West Cesar Chavez
Austin, TX 78701
USA
http://www.silabs.com